The present invention relates to the ergonomic grips. More specifically the present invention relates to ergonomic grips for use in sporting equipment.

Kayaking is a growing sport in the United States and throughout the world. There are a number of different types of kayaking and the boats and paddles associated therewith are designed for the particular type of activity engaged in. Thus, there are both calm water kayaks and white water kayaks along with sea or ocean kayak. For centuries, Eskimos have paddled Arctic waterways to hunt and fish in kayaks, a type of canoe built from skins stretched over a frame. Today""s high-tech versions of the kayak, made from plastic, Kevlar and fiberglass, are still decked with a cockpit for the rider, who propels the boat with a double-bladed paddle.
The sport of kayaking is growing rapidly in popularity. It is believed to be second only to snowboarding in growth. Driving that growth is a recent revolution in kayak hull design that has made doing tricks, such as wave surfing, squirts and spins, much easier. There are an estimated 1.3 million white water kayakers in the United States, 400,000 of whom can be considered xe2x80x9centhusiasts.xe2x80x9d One of the reasons for the increasing popularity of the sport it that a kayaker can experience solitude and wilderness on the one hand and excitement on the other.
Recent developments in kayaks have fueled the increased interest in the sport. In some instances, kayak builders have followed innovations in surfboards to come up with boats that xe2x80x9cplane,xe2x80x9d riding on top of the water instead of in the water.
As kayaks have improved and developed, additional sports and activities are possible. Where traditional kayakers simply traveled a waterway, modem kayakers maneuver and perform tricks to improve and demonstrate their skills. To promote these types of activities, kayak rodeos are springing up around the country. Many of today""s kayaks are specifically designed to be used in rodeos. These boats are generally small and sharply angled. These boats, however, are not ideally suited for river running in that they are too slow and do not track well. Thus, xe2x80x9cpark and playxe2x80x9d is a growing phenomenon, while down-river running is declining in popularity. This marks a radical departure from the roots of these sports, which were born from the need to get from one place to another. Thus, innovation is allowing more people to get into kayaking and to do different things on a river.
As kayak""s have evolved allowing the sport to evolve, there is also a need for improvements in paddle design. Generally, a kayak paddle is comprised of an aluminum or wood shaft. The shaft is generally approximately 1.25 inches in diameter. This diameter allows the user to directly grip the paddle. There are generally no specific grips or other structures to allow the user to securely hold the paddle. At times, the user may modify his own paddles by adding tape or other wrappings to make the paddle more comfortable and usable.
Generally, however, the development and improvement of the paddle has not kept pace with development in the kayaks themselves. In particular, kayak paddles have not been designed to address the injury that can be associated with kayaking. New designs in paddles have tried to address the risk of injury to the shoulder, elbow, and wrist. Many manufacturers state that their product is xe2x80x9cergonomically designed,xe2x80x9d but provide little information on how the products are ergonomic. Ergonomics come from the Greek words xe2x80x9cergos,xe2x80x9d meaning work, and xe2x80x9cnomos,xe2x80x9d meaning knowledge. Ergonomics involves adapting a tool or other object to the needs of the worker or user, rather than trying to make the worker adjust to the tool. However, little information is available about how to design an ergonomically correct grip, especially a paddle grip.
A major motivation for ergonomic design is the improved performance and health of the user of the tool. In the field of kayaking, fatigued or uncomfortable kayakers are less capable of maintaining safe performance of their task. If they are required to perform repeatedly and beyond their physical capabilities, breakdown and injury will recur. The resulting injury is what is commonly classified as a cumulative trauma disorder. Injuries that occur with poor ergonomic design are usually disorders of wear and tear, including overuse syndromes, repetitive strain injuries, musculoskeletal injuries, and compressive neuropathies. Injuries common to kayaking include carpal tunnel syndrome, wrist tendinitis, medial or lateral elbow epicondylitis, and rotator cuff muscle strains and tears. Cumulative nature of these injuries indicates the injury occurs over a period of weeks, months, or even years, or as the result of repeated stresses on a particular musculoskeletal area. Each repetition of an activity can produce a small trauma to the tissues and joints of the body.
Although the human body has enormous self-repair abilities, continued exposure to stress can outweigh these abilities, which then results in injury. Factors such as force strength, high repetition, awkward posture, reduced recovery time, and environmental factors like vibration and cold exposure can lead to injury over time. All of these factors can produce injury alone, but the incident of injury is increased when these risk factors are combined. The simple activities of repetitive gripping, twisting, reaching, and moving can be hazardous when repeated numerous times over an extended period.
Static overloading results from muscles being subjected to too much stress over a period of time. The small muscles of the hand and the extensor muscles of the wrist are most vulnerable to static overloading. These muscles stabilize the hand during forceful use and balance the extensor tendons during fine manipulation. Sustained contraction can result in tendinitis, especially about the elbows. Spreading the load over as many muscle groups as possible will help to avoid overloading the smaller muscle groups. In the case of kayaking, inappropriate paddle design can increase the risk of injury to the hand, arms, shoulders, and back. Because kayaking involves repetitive use of a hand tool, namely the kayak paddle, a kayak paddle can be designed according to ergonomic standards.
Poor paddle design can overstress the muscles, resulting in fatigue and unnecessary dissipation of energy for paddle retention. When a paddle does not properly fit in a user""s hand or becomes wet and slippery, a user may exert a large force to grip the paddle. Such power gripping requires force greater than 50 pounds per hand and can be detrimental. If the wrist is also used to exert the force, a grip force of 32 pounds is acceptable. Because of their lack of bony and muscular protection, the neurovascular bundles of the fingers are very susceptible to contact stresses. Handles that are profiled for the fingers and lack of protective cushioning make these areas susceptible to trauma.
Another consideration in designing an ergonomic tool such as a kayak paddle is maintaining adequate blood flow in the muscles. During muscular contraction, blood flow can be impeded to levels as low as 40% of the maximal voluntary contraction for the muscle. Static muscle contractions reduce the blood flow as long as the contraction is maintained. Metabolites accumulate and oxygen to the muscle can be quickly depleted, resulting in fatigue. Muscle fatigue, defined as a decreased force generating capacity, develops gradually during exercise and is distinct from exhaustion, which occurs when the hard force or exercise intensity can no longer be maintained.
The position of the forearm and wrist during paddling are also important. It is well known that when the wrist deviates from the neutral the strength of a user""s grip is reduced thereby requiring the user to exert a greater force to hold the handle. Different postures appear to result in compressive and shearing forces on the tendons, which may be transferred to adjacent nerves. The eventual consequence of this is a development of tendinitis, joint strain, and peripheral neuropathies such as carpal tunnel syndrome.
Moreover, kayakers are frequently exposed to environmental conditions, such as cold and vibration, which have been shown to cause problems as well. Cold handles can result in vasoconstriction and decreased blood flow during forceful gripping, thereby increasing the effort required. Vibration has been shown to contribute to compressive neuropathies and tenosynovitis.
Conventional kayak paddles are not ergonomically designed. These design deficiencies can lead to static overload of muscles, joints, tendons, and ligaments. Over time, serious injury can occur to the bones and muscles of a kayaker. Additionally, the use of conventional kayak paddles can result in vasoconstriction and decreased blood flow to the hands thereby increasing the possibility of injury. The poor paddle design can cause damaging compressive forces. Because kayakers are confined to wet and cold environments the chances of injury are high.
Therefore, it would be advancement in the art to provide an ergonomic kayak paddle. It would be a further advancement to provide a kayak paddle that could relieve damaging stress. It would be a further advancement if the kayak paddle reduced vasoconstriction. It would be an additional advancement in the art to provide a kayak paddle that reduced compressive forces. It would be a further advancement if the ergonomic kayak paddle could reduce the overall chance of injury to the kayaker. Such a paddle is disclosed and claimed herein.
The present invention relates to an ergonomic handle for use with a tool such as a kayak paddle. In general, the handle of the present invention may be used with a kayak paddle, however other paddles, tools, and the like may be designed using the ergonomic characteristics of the handle of the present invention. The handle has at least one grip which is disposed about the shaft of the handle. The grip has a gripping surface for accommodating the hand of a user. The shaft of the handle has a longitudinal axis running from a first end of the shaft to a second end of the shaft.
The paddle grip may be designed to maintain the user""s wrists in a neutral position during the motion of the paddle. The neutral position is defined by alignment of the third metacarpal with the radius of a user. When a straight shaft is grasped, these bones are not aligned. With the wrist out of the neutral position, the user""s ability to grip the paddle may be lessened. The user may compensate for this reduction with other muscles and bones, which may lead to an injury. Angling the grip away from the shaft allows the user""s wrist to be maintained in the neutral position. The grip may therefore be constructed such that a portion of the gripping surface designated the upper surface of the grip, is angled away from the shaft at an angle ranging from about 10xc2x0 to about 30xc2x0. In certain configurations, the angle is between about 12xc2x0 to about 28xc2x0. Alternatively the angle may be between about 22xc2x0 and about 26xc2x0. In one presently preferred embodiment the angle is about 24xc2x0.
A kayak paddle may be provided with a grip designed to ergonomic standards. One consideration for the grip is the positioning of the wrist and forearm of the user in a neutral position while holding the handle. When the upper surface of the grip is angled away from the shaft, the wrist and forearm may be positioned in a more neutral position when compared to a straight shaft. The grip may also be contoured to the hand of a user. The contour allows the grasping force to be spread evenly along the hand. However, when channels for the user""s fingers are provided, the grip may not properly fit all users causing fatigue and stress on the user""s hand. The grip may have a textured surface for engaging the user""s hand. The textured surface may allow for the distribution of stress throughout the hand and allow for better blood circulation.
The grip may be sized to generally fit within the palm of a user""s hand. A grip length of about 10 to about 12 centimeters will allow the grip to fit within the palm of the hand of most users. The diameter of the grip may also be sized to fit within the palm of a user. Generally, a diameter that is about 1 centimeter smaller than a user""s inside grip is sufficient. The shaft may have a diameter in the range of from about 0.75 to 1.00 inch which accommodates correct sizing of the paddle grip.
Additional ergonomics may be achieved by sizing the length of the shaft of the paddle to the user. Thus, a larger person may require a longer paddle to reduce the amount of leaning and twisting required to place the paddle in the water. A shorter person may also require a somewhat shorter shaft to position the paddle in the water without undue stress. When the paddle is used by more than one kayaker, the paddle may be designed with an adjustable shaft. Thus, the shaft can be provided with an adjustment mechanism to adjust its length to properly fit a user of any size.
Often a paddle will be used by more than one user. Thus, providing a grip that can be adjusted to fit more than one user is beneficial. The grip may be configured to allow for the adjustment of the angle of the grip with respect to the shaft. An adjuster may be positioned within the grip to change the angle of the grip. Such adjusters may include one or more set pins disposed in one end of the grip. Other adjusters may include a ratchet device or shunts positioned between the grip and the shaft.
Another commonly associated problem that can lead to injury is the tendency of a user to forcefully and continuously grip the paddle for an extended period of time. Often a user will kayak for hours at a time. The paddle must be continuously gripped even when not paddling to prevent the kayaker from dropping the paddle in the water. A hand strap may be connected to the in shaft allowing for a user to loosen his hold on the paddle without risking dropping the paddle.
Another consideration in the ergonomic paddle is the relative placement of the hands on the paddle. To maintain the position of the hands in an ergonomically correct position, the grips may be attached to the shaft by a releasable attachment mechanism such that the grip may be rotated about the longitudinal axis of the shaft. Such releasable attachment mechanisms may include, but are not limited to, a set screw and a clamp.
The ergonomic kayak paddle of the present invention provides at least one grip which allows the user to grasp the paddle. The grip is angled such that the wrist and forearm of the user is maintained in the neutral position. The grips can be rotated and adjusted to customize the ergonomic fit to a particular user. Moreover, the length of the paddle may be adjusted to accommodate multiple users sharing the kayak paddle. These and other features, and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.